The present invention relates to a blade holding device of a blade slide for a scrap cutter in which a slanted blade is fastened in a cutout of a blade slide with blade securing screws and blade securing nuts, and is secured against sliding in a vertical rearward blade contact surface of the blade slide in a form-locking manner with sleeves that are concentrically arranged about a shaft of the blade securing screws.
A blade holding device in which the blade is exchangeably arranged in a chuck made of hardened steel and in which the blade bolt is protected against transverse loads by relief sleeves is disclosed in a publication by Thyssen (THYSSEN HENSCHEL; Henschel-Schrottaufbereitungsanlagen; Report 2/87; Maschinen, Anlagen und Verfahren fur die Schrottaufbereitung).
The relief sleeves mentioned therein correspond to the sleeves referred to in the preamble of claim 1. They consist of hardened steel, they have thin walls and do not have a slot. The inner and the outer diameter of the sleeves are selected such that there is a small tolerance provided between the receiving bores of the blade or the chuck and the sleeve as well as between the outer diameter of the blade bolt and the inner bore of the sleeve. The tolerance between the receiving bores and the sleeves is determined such that the shearing forces are directly transferred from the blade to the chuck without transferral of forces to the sleeve.
In blade holding devices of the aforementioned kind, lateral shearing force components occur when the blade is slanted. Also, when the blade slide is moved upward, predominantly vertically acting stripping forces result from the friction between the blade and the scrap metal present in the feed channel. The sleeves arranged concentrically about the screw shaft serve to relieve the blade securing screws from the above mentioned forces.
When the blade slide remains in place, the demounting and installation of the blade in a holding device of the aforementioned kind is possible only in the longitudinal direction of the sleeves which secure the form-locking, that is, in the direction of the feed channel of the scrap cutter. However, it is then necessary to dismantle the wearing plates of the feed channel, which are overlapped by the blades, in order to have enough lateral space for the removal of the blades. The dismantling and reinstallation of the wearing plates onto the walls of the feed channel, after the blade exchange is completed, is very time consuming. In addition, the removal of the blade, after the blade securing screws have been removed, usually requires significant force because the blade as well as the blade holding device surfaces in the blade slide or the blade support are deformed by the forces acting upon the device during operation.
It is therefore an object of the present invention to improve a blade holding device of the aforementioned kind such that, while retaining the sleeves for form-locking and securing the blade, the removal and reinstallation of the blades is accomplished without dismantling the wearing plates of the feed channel.